Oil sands, also referred to as tar sands, contain a significant quantity of the world's known oil reserves. Large deposits of oil sands are found in Canada, Venezuela and in the United States in eastern Utah. Oil sands are a complex mixture of sands, clays, water and viscous hydrocarbon compounds, known as bitumen. Typically, the extraction and separation of bitumen from oil sands involves the use of significant amounts of energy and heated water. Approximately 19 barrels of water are required for every barrel of oil produced. Water, sodium hydroxide (NaOH) and other additives are mixed with the oil sands to form a slurry. The NaOH releases surfactants from the oil sands and improves bitumen recovery. The slurry is conditioned by mixing and/or shearing the slurry to detach bitumen from the oil sands particles. Bitumen is separated from water by aeration to form an oil containing froth that can be skimmed off the surface of the water. The remaining process water is a complex mixture of alkaline water, dissolved salts, minerals, residual bitumen, surfactants released from the bitumen and other materials used in processing. Additional processing of the water is required to remove residual bitumen
The process water is ultimately stored in tailing ponds and is acutely toxic to aquatic life. The process water recycled from tailings ponds causes scaling and corrosion problems that often adversely affect the optimum recovery of bitumen. In addition, very fine mineral particles such as clays are co-extracted with the bitumen and must be removed in subsequent processing steps that ultimately reduce the yield of bitumen. Although a large proportion of the water used in the process (about 16 barrels) is now recycled from tailing ponds, the production of each barrel of oil still requires importing an additional 3 barrels of fresh water. The necessity of large quantities of water has prevented the recovery of bitumen deposits from oils sands in arid areas such as Utah.
Several other related scenarios require the removal of oil from sand or solid particles in oil and gas operations. For example, heavy oil (e.g., between 10° and 20° API gravity) is also found in sand deposits, particularly in Venezuela and Canada. Recovery of heavy oil from sand typically involves expensive thermal methods such as, steam injection. A technique widely used in Canada called cold heavy oil production with sand (CHOPS) has also been used to separate heavy oil from sand. CHOPS involves the continuous production of sand and oil, which presents separation and disposal constraints.
During drilling operations drilling fluids used to cool and clean the drill bit become contaminated with formation cuttings. Formation cuttings must be removed from the drilling fluid before reuse of drilling fluid. During production operations, crude oil produced from unconsolidated formations can also contain sand including mixtures of various minerals and silt that require removal prior to processing the oil. The oil coated sand must also be cleaned before disposal or re-depositing.
An increase in offshore drilling operations has also increased the risk of coastal communities and beaches being exposed to crude oil produced from offshore oil rigs. As described above, current methods for the removal of oil from sand require large quantities of water and energy. Physical methods for removing oil from beach sand including the use of shovels, cleaning forks and lift and screen systems require large amounts of labor and do not efficiently remove all the decontaminate from the sand.
In view of the foregoing, there is a need in the field of art for improved systems, methods and compositions for the separation and recovery of hydrocarbons from particulate matter.